added resources
I did:
- our spaceship, looked from 5 views, 
- added icon for bonuses - tool for repair and gun, 
- added 4 kinds of enemies, 
-added sprite with bullets,
- and background. The background stars can move later, for now they are static.
//TODO
-implement bonuses
-implement the 4 kinds of enemies
-add explosion when enemy is dead
- eventually add some asteroids